Flexible printing-form and means for securing the same in place



' (No Model.)

W. C. WENDTE. FLEXIBLE PRINTING FORM AND MEANS FOR SEGURINGTHE SAME INPLAGE.

Patented N0 Nv PETERS, Phohrulhognpher, wnhin tnn. 0.0.

UNITED STATES PATENT OFFICE.

\VILLIAM C. IVENDTE, OF LANCASTER, ASSIGNOR TO \VILLIA M H. FORBES,

' OF. BOSTON, MASSACHUSETTS.

ELEXIBLE PRINTING-FORM AND MEANS FOR SECURING THE SAME IN PLACE.

SPECIFICATION forming part of Letters Patent No. 415,132, dated November12, 1889.

7 Application filed December 26, 1888. Serial No. 294,627- (No model.)

To all whom it nutg concern:

Be it known that 1, WILLIAM C. WENDTE, a citizen of the United States,and a resident of Lancaster, in the county of WVorcester and State ofMassachusetts, have invented a new and useful Improvement in FlexiblePrinting-- holding a flexible form in position for print ing. Fig. 2 isa view of the same seen from above, but part of the form is cut away andpart of. the clamping-strip, removed to make the construction moreintelligible. Fig. 3 is a View of the clamping-strip as seen from below.Fig. at is a side elevation of the clamp ing-strip alone, showing itsrecessed side. Fig. 5 is an end elevation of the same, and Figs. 6 and 7show an edge view of the projecting strip upon the flexible sheet ofmetal constructed in two different ways.

In the drawings, 10 is a supporting form-surface, upon which a flexiblesheet of zinc 11, or its equivalent, is to be secured. This isaccomplished with the help of the strainingbar 13, placed across thepress in the depression or gap 14 made for that purpose. This bar mayextend from side to side of the formcylinder, or may be as long as thewidth of the sheet of metal which is to be held by it.

The manner in which the attachment of the flexible form to thestraining-bar is accomplished is an essential part of my invention.Hitherto it has been the usual custom to hold the ends of a flexiblemetal sheet which is to act as a form in the printing-press by simplygrasping its extremities between jaws, which pinch it in the manner of avise, the friction produced thereby giving security to the grip. Toinsure success by such means, great force had to be exerted by theclamp, which occasioned trouble and loss of time, and when all was donedid not always gain the end in viewnamely, the positive holding of the.

metal plate. To enable the zinc to be held in such a way by the bar asto render its escape impossible,l provide a clamp ofpeculiarconstruction on the upper faceof the strainingbar, and I alsoprepare the end edges of the zinc in a novel manner for seizure by saidclamp. These arrangements are accomplished as follows:

In the straining-bar 13 a V-shaped groove is formed which runs itsentire length, and an independent clamping-strip15 is shaped like awedge to correspond substantially with said groove. This is forced intothe same by the clamping-screws 17. The flexible form 11. has left orconstructed on its end edge the projection shown at 12, which is a partof the plate itself. This strip fits a depression, notch, or recess 15on one side of the wedgeshaped clamping-strip 15, while the projectingpart at 16 butts solidly against the upturned shoulder or edge of thezinc in contact with it. Then, as shown in the drawings, the sheet ofmetal is bent downward and inserted between the recessed side of theclampingstrip 15 and the flat side of the V-shaped groove, and theformer is then depressed by means of the screws 17, the two opposed andparallel faces, acting like the jaws of a vise,

approach each other and grasp the thin metal betweenthem, so that it ispractically inextricable, except by releasing the screws 17. In clampingby this device it will be seen that the pressure exerted by the clampingscrews is much increased upon the sheet metal by reason of the wedgeshape given tothe strip 15. This way of applying the necessary pressureI bGllGXG to be the best, because of the advantages stated and for thereason that, while the stiffness and solidity of the straining-bar isincreased, all the movable parts used in grasping the ends of theflexible form can be easily kept clear of the form-rollers;

to embrace the ends of the flexible form which overhang the supportingform-surface and to fit the projections upon the same, substantially asabove described.

\Vhen the sheet of zinc or other metal constituting the form which is tobe held is moderately thick, I prefer to make the shoulder on the sameby protecting with an etchingground the strip which is to become theprojeet-ion, and then etching down the metal inside said strip with anacid; or, with the help of a simple planing-tool,I cutaway the metalmechanically parallel to the edge, leaving the projection stand, in away that will be readily understood; but when the sheet of zinc is sothin that the removal of its substance to the requisite depth wouldweaken it too much and endanger its tearing, I proceed by turning overthe edge of the metal and flattening it down in the manner shown in Fig.7, so as to give rise to apt-ejection 12,which is double the thicknessof the original plate, or a narrow parallelstrip of thin zinc maybesoldered down upon the end of the form in the position which the turnedover strip would take. \Vhen in place and grasped by the clamp, theflexible form so prepared behaves exactly as if the projection weresolid, as shown in Figs. 1 and (3.

The straining-bar shown in the drawings is adjusted,controlled, andfixed in position by the screws 18 and 19 and the bolts 20. The longscrews 18 butt against the side of the gap 14 and force the barbackward, thereby drawing the sheet of metal held by its clamp tightlyover the supporting fornrsurface 10. The screw 19, and a correspondingone at the other end of the bar, butt against the ends of the gap andserve to move the bar to and fro in the direction of its length. henproperly placed, the bolts 20 hold it firmly, and with it the flexibleform attached thereto. These adjusting devices need not be more fullydescribed in this specification, because they are not my invention, noran indispensable part of the improvementsI have made.

In the foregoing statement of my invention and in the drawings, onestraining-bar only, with the clamp forming part of the same, has beendescribed and shown, as well as only one end of the zinc form with itsrelatively thickened edge. It need hardly be said that in most caseseach flexible form is manipulated by two bars, one connected with eachend thereof, and that one bar and its appurtenances is an exactduplication of the other.

\Vhat I claim is- 1. In a printing-press, the combination of asupporting form-surface, a flexible form provided with a flat projectingstripleft or added at its end, and a straining-bar having a clampconstructed to embrace and grasp said projection, substantially asdescribed.

2. In a printing-press, the combination of asupporting form-surface, aflexible form provided with a projection at its end, a straining-bar foradjusting and holding said form, and a clamp connecting the bar andform, consisting of the bar provided with a V- shaped groove, and awedge-shaped recessed strip fitted thereto, substantially as described.

A straining-bar provided with a clamp consisting of two opposing jaws orsurfaces approached by screws, one of the same being notched or recessedto receive a flat projecting strip on the end of the flexible formcontrolled by said strainingbar, substantially as described.

4. A Straining bar provided with a clamp consisting of a bar having aV-shaped depression filled by a wedge-shaped strip, and controlled byscrews, one of the sides of said wedge being notched or recessed to [ita projection on the end of the flexible form controlled by saidstraining-bar, substantially as described.

5. The combination, with a straining-bar provided with a V-shaped groovealong its length, of a wedge-shaped clamping-strip fitting into saidgroove, and recessed on one of its sides to receive the relativelythickened edge of a flexible form, and with tighteningscrews to holdsaid clamping-strip in place, substantially as described.

6. A flexible form for printing purposes provided at its ends withrelatively thickened edges formed of fiat projecting strips by which itmay be firmly seized and held, substantially as described.

7. In a printing-press, an adjustable straining-bar carrying a clampadapted to seize and retain a flat thickening strip on the end edge of aflexible form, when the sameis in position upon its supportingform-surface, substantially as described.

WILLIAM C. \VENDTFI.

Witnesses:

Ms. B. BELL, HORACE D. GOVE.

